решите по алгебре номер4.39.

1) 4(х+3)+5(х-3) = 105
  
4х + 12 + 5х - 15 = 105
9х - 3 = 105
9х = 105+3
9х = 108
х = 108:9
х = 12

2) 3(х+20) - 4х = 10

3х + 60 - 4х = 10
- х + 60 = 10
- х = 10 - 60
- х = - 50
х = 50

3) 2х + 3(х+10) = 380

2х + 3х +30 = 380
5х + 30 = 380
5х = 380 - 30
5х = 350
х = 350 : 5
х = 70

г) 5(х+2) - 6(х-2) = 5

5х + 10 -6х +12 = 5
-х + 22 = 5
-х = 5 - 22
- х = - 17
х = 17